smokey and choppy cold starts

Hello all,

This may be a little of a long read, but here goes...

As the weather here in southern ontario gets colder and colder, there is a more and more apparent cold starting issue with my ALH.
The easiest way to describe it, it sounds like a lumpy cam'd motor and shoots smoke out the back for a few revs then everything is normal till it sits for 8+ hours.

So the car in question:
2003 jetta w/ALH
DLC1019's mounted and balanced by DBW on stage 5 pop pressures
11mm pump w/ lift pump
ARP head studs
17/22 turbo
FMIC w/3bar map
2.5" straight pipe exhaust
mafless tune

Now what i've done:
Compression check, 400 across the board
Moved the pump timing back and forth across the timing range.
Replaced the starter ( old one was lazy ) , glow plus, maxxed out the glow plug adjustment via vag-com. Played around with SOI in the tune, as well as raising minimum fuel RPM from the pump voltage, all no change.

So should i be looking at the pump as the issue? Software? IQ?

Also, whats the "normal" fuel temps for an 11mm pump? I'm seeing 110+ while out driving around... Eesh...

Here is a good youtube video showing it its worst its been... ( enjoy the "really canadian eh? Accent... Ha! )
http://www.youtube.com/watch?v=TwkdUmCN_xU


Thanks!

I have the same issue with my 2001 stock Jetta tdi, but yours blows out more smoke then mine. In the mornings in California (average 64F) it has that lumpy smokey cold start & it doesn't any further until it sits overnight. My battery recently went dead and I thought that could of been the issue for a weak cold start, but a new battery didn't fix the issue either. I also notice I don't hear a buzzing sound coming from the rear passenger seats and thought it could be a lift pump issue causing this. The only stuff I did to the car when i first purchased it was delete the cat, replace n75, replaced all vacuum lines, new oem egr valve, and cleaned the turbo with the oven cleaner.

Check your glowplugs. They do come on for a few minutes after the motor starts under all conditions.
Glow plugs do not come on before you start unless ambient temperature is 9 deg. C or less despite what the light may show.
Unplug the the temperature sender to force a glowplug cycle before starting assuming they all work.

just out of curiosity...how many kms on the engine and IP?

A 2001 Jetta does not come equipped with an in-tank lift pump unless one was added.

maxmoo said:

just out of curiosity...how many kms on the engine and IP?

Click to expand...

Pump has 15x,000 km, engine is at 46x,000 km.

Mako said:

Check your glowplugs. They do come on for a few minutes after the motor starts under all conditions.
Glow plugs do not come on before you start unless ambient temperature is 9 deg. C or less despite what the light may show.
Unplug the the temperature sender to force a glowplug cycle before starting assuming they all work.

Click to expand...

I'll give that a try tomorrow morning, that'll max out their burn time...

If you have only 400 psi across, that may be the issue. Should be at least 450-500+ on a healthy alh

I can see your point,

But from my understanding a ~500PSI compression is "perfect" compression number, And 275PSI is the wear limit/bad compression.

If i exhaust all other options, I guess an engine rebuild is in order.

I unplugged the temp sensor, it cut out easily half of the surging in the reves, but they where still present as was the white smoke....

Is a fuel temp of 100+ "normal" for an 11mm pump after a bit if driving in 60f weather?
The IQ may be a little low for the fuel the pump map is requesting, and the fuel temp sensor could be hooped.

Just a spit ball here...

My ALH isn't as heavily modded(listed in signature), but I had an issue with shaky starts after chipping it. I spoke to Mark and he suggested to change the IQ. It sat around 2.75 at idle with the engine warm and had no sputtering. It would, however sputter, stutter, smoke a bit much and rev itself on starts after sitting overnight. This was happening in the summer. After Mark suggested to change the IQ to 3, it went away. I do not have logs or graphs, as I am new to VCDS/VAGCOM, but changing that one number made it start and run great! I believe my timing was not a factor and is set to factory. I should mention that my sedan is a 2003, auto, with about 162,xxx miles. Hope this helps.

I'm going off of memory here, but i'm almost positive that my IQ is 3-3.5...
I'll connect vag-com tonight and back it off and see where that takes me.

Did you check compression when the engine was warm? Try checking compression after the engine sits over night. There could be an underlying problem when cold.

Healthy TDI's hit 450-550psi on compression check. 400psi is not bad, and as long as all 4 cylinders are consistent within 10psi then I would not put too much time into that one. Unless cold compression numbers are different.

The compression check was done roughly two hours after the car was drivin at operating temp...
So yeah, it definitely had some heat in it.

I'll see if i can make some time to park it at the shop one night and test it in the morning..

The pressures where something like 396 401 398 405 iirc... They where all within the 10% rule, and nothing standing out.